This invention relates to a bootstrap push pull stage. More specifically, this invention relates to a digital monolithic integrated bootstrap push pull stage using insulated-gate field-effect transistor technology (MOS technology). Such a stage comprises two enhancement-mode output-stage transistors having their drain-source paths connected in series between the supply voltage and ground. A bootstrap capacitor has one of its terminals connected to the gate of the output-stage transistor coupled to the supply voltage, whereby the bootstrap node is formed, and has its other terminal connected to a point following the potential of the output of the bootstrap push-pull stage. The bootstrap push-pull stage further comprises a first charge pump circuit having its clock input connected directly to the output of a clock oscillator and having its first direct-voltage terminal, whose polarity is opposite to that of the supply voltage, connected to the supply voltage, and the inverters and capacitors.
A bootstrap push-pull stage of this kind is disclosed in Offenlegungsschrift DE No. 23 59 646. In that stage, manufacturing variations affecting the gate voltage are compensated for, so that operation within a linear range is ensured. The parameters of stages fabricated together with their load circuits on different semiconductor wafers vary if an externally generated gate voltage common to all push-pull stages is applied.